We read (Mu. Up. II, 2, 10, and Ka. Up. V, 15), 'The sun does not shine there, nor the moon and the stars, nor these lightnings, much less this fire. After him when he shines everything shines; by the light of him all this is lighted.' The question here arises whether he 'after whom when he shines everything shines, and by whose light all this is lighted,' is some luminous substance, or the highest Self (praj/n/a atman). A luminous substance, the purvapakshin maintains.--Why?--Because the passage denies the shining only of such luminous bodies as the sun and the like. It is known (from every-day experience) that luminous bodies such as the moon and the stars do not shine at daytime when the sun, which is itself a luminous body, is shining. Hence we infer that that thing on account of which all this, including the moon, the stars, and the sun himself, does not shine is likewise a thing of light. The 'shining after' also is possible only if there is a luminous body already, for we know from experience that 'acting after' (imitation) of any kind takes place only when there are more than one agent of similar nature; one man, for instance, walks after another man who walks himself. Therefore we consider it settled that the passage refers to some luminous body. To this we reply that the highest Self only can be meant.--Why?--On account of the acting after. The shining after mentioned in the passage, 'After him when he shines everything shines,' is possible only if the praj/n/a Self, i.e. the highest Self, is understood. Of that praj/n/a Self another scriptural passage says, 'His form is light, his thoughts are true' (Ch. Up. III, 14, 2). On the other hand, it is not by any means known that the sun, &c. shines after some other luminous body. Moreover, on account of the equality of nature of all luminous bodies such as the sun and the like, there is no need for them of any other luminous body after which they should shine; for we see that a lamp, for instance, does not 'shine after' another lamp. Nor is there any such absolute rule (as the purvapakshin asserted) that acting after is observed only among things of similar nature. It is rather observed among things of dissimilar nature also; for a red-hot iron ball acts after, i.e. burns after the burning fire, and the dust of the ground blows (is blown) after the blowing wind.--The clause 'on account of the acting after' (which forms part of the Sutra) points to the shining after (mentioned in the scriptural /s/loka under discussion); the clause 'and of him' points to the fourth pada of the same /s/loka. The meaning of this latter clause is that the cause assigned for the light of the sun, &c. (in the passage 'by the light of him everything is lighted') intimates the praj/n/a Self. For of that Self Scripture says, 'Him the gods worship as the light of lights, as immortal time' (B/ri/. Up. IV, 4, 16). That, on the other hand, the light of the sun, the moon, &c,